Semiconductor device and manufacturing method therefor

ABSTRACT

The present disclosure relates to the technical field of semiconductor processes, and discloses a semiconductor device and a manufacturing method therefor. The manufacturing method includes: providing a substrate structure including a substrate and a first material layer on the substrate, wherein a recess is formed in the substrate and the first material layer includes a nanowire; forming a base layer on the substrate structure; selectively growing a graphene layer on the base layer; forming a second dielectric layer on the graphene layer; forming an electrode material layer on the substrate structure to cover the second dielectric layer; defining an active region; and forming a gate by etching at least a portion of a stack layer to at least the second dielectric layer so as to form a gate structure surrounding an intermediate portion of the nanowire, where the gate structure includes a portion of the electrode material layer and the second dielectric layer. The present disclosure incorporates graphene into the semiconductor process and makes use of the features of graphene in a dual-gate structure.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 15/683,029(still pending), filed on Aug. 22, 2017 which claims priority to ChinesePatent Application No. 201610871339.8, filed Sep. 30, 2016, the entirecontents of each of which is incorporated herein by reference.

BACKGROUND Technical Field

The present disclosure relates to the field of semiconductors,particularly to a semiconductor device and a manufacturing methodtherefor, and more particularly to a graphene semiconductor device and amanufacturing method therefor.

Related Art

With the constant development of semiconductor technologies, the size ofsemiconductor devices becomes smaller. The size of semiconductor devicesbased on silicon materials has evolved according to the Moore's Law forabout 40 years. The Complementary Metal Oxide Semiconductor (CMOS forshort) technology can almost be considered as the cornerstone of thedevelopment of the global information technologies. Semiconductordevices based on silicon materials will still be the mainstream of thedevelopment of semiconductor technologies at least for an indefinitelylong period of time in the future. However, to ensure that thesemiconductor technologies can continue to evolve according to theMoore's Law, only reducing the device size proportionally cannotsufficiently meet the requirements. Therefore, new materials need to beintroduced into the existing CMOS manufacturing process, so as tofurther lower the production and manufacturing costs, improve the deviceperformance, and reduce power consumption due to leakage current.Graphene-based electronic devices are considered to be one of thecandidate solutions for semiconductor devices.

SUMMARY

To address at least one of the foregoing problems, the presentdisclosure proposes the at least the following forms of implementations.

According to an aspect of the present disclosure, a method formanufacturing a semiconductor device is provided. The method includes:providing a substrate structure, including a substrate and a firstmaterial layer on the substrate, wherein a recess is formed in thesubstrate and the first material layer includes a nanowire spanning andsuspended above the recess; forming a base layer on the substratestructure, where the base layer includes at least a first portioncovering an exposed surface of the nanowire and a second portioncovering an exposed surface of the recess; selectively growing agraphene layer on the base layer; forming a second dielectric layer onthe graphene layer; forming an electrode material layer on the substratestructure to cover the second dielectric layer; partially removing theelectrode material layer, the second dielectric layer, and the graphenelayer so as to define an area of an active region wherein at least aportion of a stack layer of the electrode material layer, the seconddielectric layer, and the graphene layer on the nanowire remains and iswithin the active region; and forming a gate by etching at least aportion of the remaining stack layer within the active region to atleast the second dielectric layer so as to form a gate structuresurrounding an intermediate portion of the nanowire, where the gatestructure includes a portion of the electrode material layer and thesecond dielectric layer.

In a form, after defining the gate, the method further includes:removing portions of the graphene layer and the second dielectric layeron a surface of the recess.

In a form, defining the active region includes: forming a patterned maskon the electrode material layer, the patterned mask shielding at least aportion of the nanowire; and removing, by using the patterned mask,portions of the electrode material layer, the second dielectric layer,and the graphene layer not shielded by the patterned mask.

In a form, the patterned mask shields the nanowire and at least aportion of the recess.

In a form, the substrate includes a substrate layer and a firstdielectric layer on the substrate layer, wherein the first materiallayer is on the first dielectric layer; the recess is formed in thefirst dielectric layer; and providing a substrate structure includes:providing an initial substrate structure including the substrate and thefirst material layer on the first dielectric layer; patterning the firstmaterial layer to define a region covering the nanowire and two sides ofthe nanowire along the length direction of the nanowire; and removing atleast upper portions of the first dielectric layer of the defined regionto form the recess.

In a form, the recess further extends through the first dielectric layerinto the substrate layer.

In a form, the graphene layer includes a first portion on a surface ofthe first portion of the base layer, and a second portion on a surfaceof the second portion of the base layer; the second dielectric layerincludes a first portion on a surface of the first portion of thegraphene layer, and a second portion on a surface of the second portionof the graphene layer; and wherein the electrode material layer isfurther formed to fill a space below the nanowire and between the firstportion of the second dielectric layer and the second portion of thesecond dielectric layer when forming the electrode material layer.

In a form, the first material layer further includes a portion above thefirst dielectric layer at two ends of the recess bonded to the portionof the first material layer forming the nanowire; and the patterned maskshields the nanowire, and further shields at least a portion of thefirst material layer that is bonded to the nanowire.

In a form, the first material layer comprises polysilicon, dopedpolysilicon, or silicon germanium; the base layer comprises an oxide ofaluminum; the first dielectric layer comprises an oxide of silicon; andthe second dielectric layer comprises boron nitride, an oxide ofsilicon, an oxide of hafnium, an oxide of aluminum, or a nitride ofaluminum.

In a form, the material of the base layer includes an oxide of aluminum,and selectively growing the graphene layer on the base layer includesselectively growing the graphene layer at a temperature of 900-1000° C.by a chemical vapor deposition process using methane and hydrogen.

In a form, the nanowire comprises doped polysilicon; and the portion ofthe electrode material layer in the gate structure is used as a firstgate, and the nanowire is used as a second gate.

In a form, forming the gate includes: forming a third dielectric layerto cover at least the substrate structure and the area of the activeregion; and etching, by using a patterned mask defining a gate area, aportion of the third dielectric layer outside the gate area and at leasta portion of the stack layer within the active region but outside thegate area to at least the second dielectric layer so as to form a gatestructure surrounding an intermediate portion of the nanowire, where thegate structure includes a portion of the electrode material layer andthe second dielectric layer.

In a form, the method further includes: forming a fourth dielectriclayer to at least cover the substrate structure and the area of theactive region; forming a hole through the fourth dielectric layer andthe second dielectric layer to the graphene layer, the hole beingseparated from the gate structure; and filling the hole with aconductive material, so as to form a contact component to the graphenelayer.

In a form, after the gate defining processing, the method furtherincludes: forming a fourth dielectric layer to at least cover thesubstrate structure and the area of the active region; forming a holethrough the fourth dielectric layer, the second dielectric layer, andthe graphene layer to the first material layer; forming an insulatingmaterial layer on a side wall of the hole; and after the insulatingmaterial layer is formed, filling the hole with a conductive material soas to form a contact component to the first material layer.

In a form, the method further includes: forming a fourth dielectriclayer to at least cover the substrate structure and the area of theactive region; forming a hole through the fourth dielectric layer, thesecond dielectric layer, and the graphene layer to the at least aportion of the first material layer; forming an insulating materiallayer on a side wall of the hole; and after the insulating materiallayer is formed, filling the hole with a conductive material so as toform a contact component to the at least a portion of the first materiallayer, where the insulating material layer electrically isolates thegraphene layer from the contact component.

According to another aspect of the present disclosure, a semiconductordevice is provided. The semiconductor device includes: a substratestructure including a substrate and a first material layer on thesubstrate, and a recess formed in the substrate, wherein the firstmaterial layer comprises a nanowire spanning and suspended above therecess; a base layer on an exposed surface of the nanowire; a graphenelayer on the base layer; a second dielectric layer on the graphenelayer; and a gate structure surrounding an intermediate portion of thenanowire, where the gate structure includes a portion of the electrodematerial layer and the second dielectric layer surrounding the portionof the second dielectric layer.

In a form, the substrate includes a substrate layer and a firstdielectric layer on the substrate layer, wherein the first materiallayer is on the first dielectric layer, and the recess is formed in thefirst dielectric layer.

In a form, the recess further extends through the first dielectric layerinto the substrate layer.

In a form, the gate structure further includes a portion in the recessbelow the nanowire.

In a form, the first material layer further includes a portion above thefirst dielectric layer at two ends of the recess bonded to the portionof the first material layer forming the nanowire.

In a form, the first material layer comprises polysilicon, dopedpolysilicon, or silicon germanium; the base layer comprises an oxide ofaluminum; the first dielectric layer comprises an oxide of silicon; andthe second dielectric layer comprises boron nitride, an oxide ofsilicon, an oxide of hafnium, an oxide of aluminum, or a nitride ofaluminum.

In a form, the graphene layer is selectively grown on the base layer.

In a form, the nanowire comprises doped polysilicon; and the portion ofthe electrode material layer in the gate structure is used as a firstgate, and the nanowire is used as a second gate.

In a form, the device further includes: a second base layer on anexposed surface of the recess; a second graphene layer on the secondbase layer; and a second dielectric layer on the second graphene layer,where the base layer is integrally formed with the second base layer,the graphene layer is integrally formed with the second graphene layer,and the second dielectric layer is integrally formed with the seconddielectric layer.

In a form, the device further includes: a fourth dielectric layer,covering at least the substrate structure and the nanowire on which astack layer of the base layer, the graphene layer, and the seconddielectric layer is formed; a hole through the fourth dielectric layerand the second dielectric layer to the graphene layer; and a contactcomponent filling the hole and to the graphene layer.

In a form, the device further includes: a fourth dielectric layer,covering at least the substrate structure and the nanowire on which astack layer of the base layer, the graphene layer, and the seconddielectric layer is formed; a hole through the fourth dielectric layer,the second dielectric layer, and the graphene layer to the firstmaterial layer; an insulating material layer on a side wall of the hole;and a contact component filling the hole and to the first materiallayer, where the insulating material layer electrically isolates thegraphene layer from the contact component.

In a form, the device further includes: a fourth dielectric layer,covering at least the substrate structure and the nanowire on which astack layer of the base layer, the graphene layer, and the seconddielectric layer is formed; a hole through the fourth dielectric layer,the second dielectric layer, and the graphene layer to the portion ofthe first material layer; and a contact component which is formed to theat least a portion of the first material layer by filling the hole witha conductive material.

According to the following detailed descriptions of the forms ofimplementations for illustration purposes of the present disclosure withreference to the accompanying drawings, other characters and advantagesof the present disclosure will become clear.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings that form a part of the specification describeforms of the present disclosure, and are used to explain the principlesof the present disclosure together with the specification.

With reference to the accompanying drawings, the present disclosure canbe understood more clearly according to the following detaileddescription, where:

FIG. 1 is a schematic flowchart of a method for manufacturing asemiconductor device;

FIG. 2A is a perspective view of a structure at a phase of amanufacturing process of a semiconductor device;

FIG. 2B schematically illustrates a cross-sectional diagram interceptedalong a line A-A′ in FIG. 2A;

FIG. 2C schematically illustrates a cross-sectional diagram interceptedalong a line B-B′ in FIG. 2A;

FIG. 3A is a perspective view of a structure at a phase of amanufacturing process of a semiconductor device;

FIG. 3B schematically illustrates a cross-sectional diagram interceptedalong a line A-A′ in FIG. 3A;

FIG. 3C schematically illustrates a cross-sectional diagram interceptedalong a line B-B′ in FIG. 3A;

FIG. 4A is a perspective view of a structure at a phase of amanufacturing process of a semiconductor device;

FIG. 4B schematically illustrates a cross-sectional diagram interceptedalong a line A-A′ in FIG. 4A;

FIG. 4C schematically illustrates a cross-sectional diagram interceptedalong a line B-B′ in FIG. 4A;

FIG. 5A is a perspective view of a structure at a phase of amanufacturing process of a semiconductor device;

FIG. 5B schematically illustrates a cross-sectional diagram interceptedalong a line A-A′ in FIG. 5A;

FIG. 5C schematically illustrates a cross-sectional diagram interceptedalong a line B-B′ in FIG. 5A;

FIG. 6A is a perspective view of a structure at a phase of amanufacturing process of a semiconductor device;

FIG. 6B schematically illustrates a cross-sectional diagram interceptedalong a line A-A′ in FIG. 6A;

FIG. 6C schematically illustrates a cross-sectional diagram interceptedalong a line B-B′ in FIG. 6A;

FIG. 7A is a perspective view of a structure at a phase of amanufacturing process of a semiconductor device;

FIG. 7B schematically illustrates a cross-sectional diagram interceptedalong a line A-A′ in FIG. 7A;

FIG. 7C schematically illustrates a cross-sectional diagram interceptedalong a line B-B′ in FIG. 7A;

FIG. 8A is a perspective view of a structure at a phase of amanufacturing process of a semiconductor device;

FIG. 8B schematically illustrates a cross-sectional diagram interceptedalong a line A-A′ in FIG. 8A;

FIG. 8C schematically illustrates a cross-sectional diagram interceptedalong a line B-B′ in FIG. 8A;

FIG. 9A is a perspective view of a structure at a phase of amanufacturing process of a semiconductor device;

FIG. 9B schematically illustrates a cross-sectional diagram interceptedalong a line A-A′ in FIG. 9A;

FIG. 9C schematically illustrates a cross-sectional diagram interceptedalong a line B-B′ in FIG. 9A;

FIG. 10A is a perspective view of a structure at a phase of amanufacturing process of a semiconductor device;

FIG. 10B schematically illustrates a cross-sectional diagram interceptedalong a line A-A′ in FIG. 10A;

FIG. 10C schematically illustrates a cross-sectional diagram interceptedalong a line B-B′ in FIG. 10A;

FIG. 11A is a perspective view of a structure at a phase of amanufacturing process of a semiconductor device;

FIG. 11B schematically illustrates a cross-sectional diagram interceptedalong a line A-A′ in FIG. 11A;

FIG. 11C schematically illustrates a cross-sectional diagram interceptedalong a line B-B′ in FIG. 11A;

FIG. 12A is a perspective view of a structure at a phase of amanufacturing process of a semiconductor device;

FIG. 12B schematically illustrates a cross-sectional diagram interceptedalong a line A-A′ in FIG. 12A;

FIG. 12C schematically illustrates a cross-sectional diagram interceptedalong a line B-B′ in FIG. 12A;

FIG. 13A and FIG. 13B are schematic diagrams that illustrate crosssections of a structure at a phase of a manufacturing process of asemiconductor device;

FIG. 14A and FIG. 14B are schematic diagrams that illustrate crosssections of a structure at a phase of a manufacturing process of asemiconductor device;

FIG. 15A and FIG. 15B are schematic diagrams that illustrate crosssections of a structure at a phase of a manufacturing process of asemiconductor device;

FIG. 16A and FIG. 16B are schematic diagrams that illustrate crosssections of a structure at a phase of a manufacturing process of asemiconductor device;

FIG. 17 is a perspective view of a structure at a phase of amanufacturing process of a semiconductor device; and

FIG. 18A and FIG. 18B are schematic diagrams that illustrate crosssections of a structure at a phase of a manufacturing process of asemiconductor device.

DETAILED DESCRIPTION

Various exemplary forms or implementations for illustration purposes ofthe present disclosure are described in details with reference to theaccompanying drawings. It should be noted that unless being described indetail, relative layouts, mathematical expressions, and numeric valuesof components and steps described in these forms do not limit the scopeof the present disclosure.

Meanwhile, it should be noted that for convenience of description, sizesof the parts shown in the accompanying drawings may not be drawnaccording to an actual proportional relationship.

The following description about at least one exemplary form isillustrative only, and would not be used as any limitation on thepresent disclosure and applications or uses of the present disclosure.

Technologies, methods, and devices that are known by a person ofordinary skill in the related art may not be discussed in detail.However, if appropriate, these technologies, methods, and devices shouldbe considered as a part of the description.

In all examples shown and discussed herein, any specific value should beinterpreted to be illustrative only rather than a limitation. Therefore,other examples of the forms may have different values.

It should be noted that the term “semiconductor device”, used in ageneral sense and when there is no other specific limitations, includesany device operating partly or entirely based on semiconductorprinciples, including but not limited to: various semiconductor elementssuch as a diode, a bipolar transistor, and a field effect transistor; anintegrated or discrete circuit, die, or chip composed of varioussemiconductor elements; and any device of the foregoing element,circuit, die, or chip. However, it should be further noted that thescope of this term may be specifically limited: in different exemplaryforms, the term “semiconductor device” may be limited, by otherdefinitions which are relevant to this term, by explicitly descriptionin the context, or by requirement of operating principles, to particularsemiconductor elements, circuits, dies, chips, or devices only.

It should be noted that similar reference numerals, labels, and lettersrepresent similar items in the following accompanying drawings.Therefore, once an item is defined in a figure, the item needs not to befurther discussed in subsequent figures.

FIG. 1 is a schematic flowchart of a method for manufacturing asemiconductor device. FIG. 2A to FIG. 16B are schematic diagrams thatillustrate a plurality of phases of a manufacturing process of asemiconductor device. Description is made in the following withreference to FIG. 1 and FIG. 2A to FIG. 16B.

As shown in FIG. 1, in step 101, a substrate structure is provided.

FIG. 2A is a perspective view of a structure in step 101 of amanufacturing process of a semiconductor device. FIG. 2B is across-sectional diagram that schematically illustrates a structure shownin FIG. 2A that is intercepted along a line A-A′. FIG. 2C is across-sectional diagram that schematically illustrates a structure shownin FIG. 2A that is intercepted along a line B-B′. Herein, it should benoted that in the accompanying drawings, an arrow related to the sectionline A-A′ or B-B′ represents a view direction.

As shown in FIG. 2A, FIG. 2B, and FIG. 2C, an initial substrate isprovided, where the initial substrate structure may include a substrateand a first material layer 204 on the substrate.

In an implementation, the substrate may include a substrate layer 200and a first dielectric layer 202 on the substrate layer 200. In such asituation, the first material layer 204 may be above the firstdielectric layer 202. The material of the substrate layer 200 mayinclude a semiconductor material such as silicon. A material forming thefirst dielectric layer 202 may include an oxide of silicon.

Subsequently, the first material layer is patterned to form a nanowire.FIG. 3A and FIG. 4A are perspective view that schematically illustrate aprocess of forming an nanowire according to a form of this application;FIG. 3B schematically illustrates a cross-sectional diagram interceptedalong a line A-A′ in FIG. 3A; FIG. 3C schematically illustrates across-sectional diagram intercepted along a line B-B′ in FIG. 3A; FIG.4B schematically illustrates a cross-sectional diagram intercepted alonga line A-A′ in FIG. 4A; and FIG. 4C schematically illustrates across-sectional diagram intercepted along a line B-B′ in FIG. 4A. Asshown in FIG. 3A, FIG. 3B, and FIG. 3C, a first protection layer 206 anda patterned mask 208 may be successively formed on the first materiallayer 204. The material of the first protection layer 206 may include,for example, an oxide of silicon or a nitride of silicon. The firstmaterial layer 204 may be formed by materials such as polysilicon, ordoped polysilicon or silicon germanium. The patterned mask may be formedby using a double patterning (double patterning) process, aself-assembly process, or a sidewall mask process. Subsequently, thefirst protection layer 206 and the first material layer 204 are etchedby using a patterned first mask 208, so as to pattern the first materiallayer 204 to form a nanowire 210 (see FIG. 4A to FIG. 4C). Then thepatterned mask 208 and the first protection layer 206 may be removed.The obtained device structure is shown in FIG. 4A-4C.

It should be noted that in FIG. 4A and FIG. 4B, a portion 211 obtainedby patterning the first material layer 204 and is at two sides of thenanowire 210 is further shown. As shown in FIG. 4A and FIG. 4B, theportion 211 does not serve as a nanowire, but in other forms, theportion 211 may be formed as a nanowire.

Subsequently, a first removing processing is performed to remove atleast upper portions of the first dielectric layer 202 which are belowthe nanowire 210 and within regions at two sides along a lengthdirection of the nanowire 210, so as to form a recess 212, as shown inFIG. 5A. In a specific form, portions of the first dielectric layer 202which are located at two sides of the nanowire 210 may be first etchedby using dry etching to be below the nanowire 210. Then wet etching isperformed, and a portion of the first dielectric layer 202 that is belowthe nanowire 210 is removed, so as to form the recess 212. FIG. 5A is aperspective view that schematically illustrates a structure in which therecess 212 is formed in this way. FIG. 5B schematically illustrates across-sectional diagram intercepted along a line A-A′ in FIG. 5A. FIG.5C schematically illustrates a cross-sectional diagram intercepted alonga line B-B′ in FIG. 5A.

In addition, as shown in FIG. 5A, FIG. 5B, and FIG. 5C, along a lengthdirection of the nanowire 210, the nanowire 210 may include a portionabove the recess 212, and a support portion 216 above edges of two endsof the recess 212 (the first dielectric layer 202). It can be seen fromFIG. 5C that the first material layer 204 includes the nanowire 210, andthe nanowire 210 spans the recess 212 and is suspended above the recess212. Therefore, in some forms, the term “nanowire” indicates, incombination with other appropriate definitions when necessary, a portionof the nanowire which spans the recess and is suspended above therecess. In the accompanying drawings, e.g., FIG. 5C, the portion of thenanowire which spans the recess and is suspended above the recess ismarked by a reference numeral 210.

In a specific form, the support portion 216 at two ends of the nanowire210 may also extend along a width direction of the nanowire 210, i.e.,the support portion 216 forms an “I” shape or an “H” shape (not shown inthe figures) with the nanowire 210, where the nanowire 210 is atransverse connecting portion in the “H” shape. That is, the firstmaterial layer 204 may further include a portion 216 at two ends of therecess 212 and above the first dielectric layer 202. Two ends of thenanowire 210 may be bonded or connected to the portion 216 of the firstmaterial 204 that is at the two ends of the recess 212 and above thefirst dielectric layer 202. In this implementation, in step 111described in the following, a patterned mask shields the nanowire 210,and further shields at least a portion of the first material layer 204that is bonded or connected to the nanowire 210.

In addition, in FIG. 5A to FIG. 5C, the recess 212 is shown as beingformed in the first dielectric layer 202. However, in another specificform, the recess 212 may further extend through the first dielectriclayer 202 into the substrate layer 200.

Subsequently, as shown in FIG. 1, in step 103, a base layer is formed onthe substrate structure.

FIG. 6A schematically illustrates a perspective view of a structure of asemiconductor device in step 103. FIG. 6B schematically illustrates across-sectional diagram of a structure shown in FIG. 6A that isintercepted along a line A-A′. FIG. 6C schematically illustrates across-sectional diagram of a structure shown in FIG. 6A that isintercepted along a line B-B′. As shown in FIG. 6A, FIG. 6B, and FIG.6C, a base layer 302 is formed on the substrate structure. The baselayer 302 includes at least a first portion 601 covering an exposedsurface of the nanowire 210 and a second portion 603 covering an exposedsurface of the recess 212. The material of the base layer 302 mayinclude an oxide of aluminum, and may alternatively include anothermaterial, known by a person skilled in the art, on which graphene can beselectively grown. The base layer 302 may be formed by using an atomiclayer deposition process.

Subsequently, as shown in FIG. 1, in step 105, a graphene layer isselectively grown on the base layer.

FIG. 7A schematically illustrates a perspective view of a structure of asemiconductor device in step 105. FIG. 7B schematically illustrates across-sectional diagram of a structure shown in FIG. 7A that isintercepted along a line A-A′. FIG. 7C schematically illustrates across-sectional diagram of a structure shown in FIG. 7A that isintercepted along a line B-B′. As shown in FIG. 7A, FIG. 7B, and FIG.7C, a graphene layer 304 is selectively grown on the base layer 302.Correspondingly, the graphene layer 304 may cover an exposed surface ofthe base layer 302, and include a first portion on a surface of thefirst portion of the base layer 302, and a second portion on a surfaceof the second portion of the base layer 302.

In a specific form, the step of selectively growing the graphene layer304 on the base layer 302 includes selectively growing the graphenelayer 304 at a temperature of 900-1000° C. by a chemical vapordeposition process using methane and hydrogen. It should be understoodthat the present disclosure is not limited thereto, but may also useother technologies for growing a graphene layer.

Subsequently, as shown in FIG. 1, in step 107, a second dielectric layeris formed on the graphene layer.

FIG. 8A schematically illustrates a perspective view of a structure of asemiconductor device in step 107. FIG. 8B schematically illustrates across-sectional diagram of a structure shown in FIG. 8A that isintercepted along a line A-A′. FIG. 8C schematically illustrates across-sectional diagram of a structure shown in FIG. 8A that isintercepted along a line B-B′. As shown in FIG. 8A, FIG. 8B, and FIG.8C, a second dielectric layer 306 is formed on the graphene layer 304.The second dielectric layer 306 may cover an exposed surface of thegraphene layer 304. Correspondingly, the second dielectric layer 306 mayinclude a first portion on a surface of the first portion of thegraphene layer 304, and a second portion on a surface of the secondportion of the graphene layer 304. The material of the second dielectriclayer 306 may include boron nitride, an oxide of silicon, an oxide ofhafnium, an oxide of aluminum, or a nitride of aluminum. The seconddielectric layer 306 may be formed by using an atomic layer depositionprocess.

Subsequently, as shown in FIG. 1, in step 109, after the seconddielectric layer is formed, an electrode material layer is formed on thesubstrate structure to cover the second dielectric layer.

FIG. 9A schematically illustrates a perspective view of a structure of asemiconductor device in step 109. FIG. 9B schematically illustrates across-sectional diagram of a structure shown in FIG. 9A that isintercepted along a line A-A′. FIG. 9C schematically illustrates across-sectional diagram of a structure shown in FIG. 9A that isintercepted along a line B-B′. In an implementation, as shown in FIG.9A, FIG. 9B, and FIG. 9C, after the second dielectric layer 306 isformed, an electrode material layer 402 is formed on the substratestructure to cover the second dielectric layer 306. The electrodematerial layer 402 is further formed to fill a space below the nanowire210 and between the first portion of the second dielectric layer 306 andthe second portion of the second dielectric layer 306 (i.e., theelectrode material layer 402 fills the recess 212). The material of theelectrode material layer 402 may include polysilicon.

Subsequently, as shown in FIG. 1, in step 111, an active region definingprocessing is performed. The electrode material layer, the seconddielectric layer, and the graphene layer are partially removed so as todefine an area of an active region. Moreover, within the area of theactive region, at least a portion of a stack layer of the electrodematerial layer, the second dielectric layer, and the graphene layer onthe nanowire is retained.

FIG. 10A to FIG. 10C, FIG. 11A to FIG. 11C, and FIG. 12A to FIG. 12Cshow the active region defining processing according to animplementation of this disclosure. In this implementation, the step ofperforming the active region defining processing includes: forming apatterned mask 404 on the electrode material layer 402, as shown in FIG.10A, FIG. 10B, and FIG. 10C. The patterned mask 404 may shield at leasta portion of the nanowire 210. FIG. 10A is a perspective view of astructure in which the patterned mask 404 is formed on the electrodematerial layer 402 according to a form of the present disclosure. FIG.10B schematically illustrates a cross-sectional diagram interceptedalong a line A-A′ in FIG. 10A. FIG. 10C schematically illustrates across-sectional diagram intercepted along a line B-B′ in FIG. 10A. Inthis form, the patterned mask 404 shields the nanowire 210 and therecess 212, as shown in FIG. 10A, FIG. 10B, and FIG. 10C.

In another specific form, the patterned mask 404 may also merely shieldthe nanowire 210 and a portion of the recess 212 (not shown in thefigures). For example, the mask 404 may be formed to have a narrowerlateral width than the mask 404 shown in FIG. 10B.

Then, portions of the electrode material layer 402, the seconddielectric layer 306, and the graphene layer 304 that are not shieldedby the patterned mask 404 are removed by using the patterned mask 404.That is, portions of the electrode material layer 402, the seconddielectric layer 306, and the graphene layer 304 (for example, theportions of the electrode material layer 402, the second dielectriclayer 306, and the graphene layer 304 that are not shielded by thepatterned mask 404) are removed. So that, the area of the active regionis defined. Then the patterned mask 404 may be removed. Perspective viewof the obtained structure is shown in FIG. 11A. FIG. 11B and FIG. 11Care sectional diagrams of FIG. 11A intercepted along a line A-A′ and aline B-B′, respectively. Within the area of the active region, at leasta portion of a stack layer, on the nanowire 210, of the electrodematerial layer 402, the second dielectric layer 306, and the graphenelayer 304 is retained.

In some forms, the stack layer of the electrode material layer 402, thesecond dielectric layer 306, and the graphene layer 304 that is in therecess 212 (or, on a surface of the recess 212) may be removed. However,in some other forms, the stack layer of the electrode material layer402, the second dielectric layer 306, and the graphene layer 304 that isin the recess 212 (or, on a surface of the recess 212) may be retained.

In another implementation, the first material layer 204 may furtherinclude a support portion 216 at two ends of the recess 212 and abovethe first dielectric layer 202, as described in one of theimplementations regarding step 101. In some forms, the patterned maskshields the nanowire 210, and further shields at least a portion of thefirst material layer 204 that is bonded or connected to the nanowire210, for example, at least a portion of the support portion 216.

Preferably, the active region defining processing may further include ashaping step, so as to process a profile of the electrode material layer402, as shown in FIG. 12A to FIG. 12C. For example, through annealing,the profile of the electrode material layer 402 may be smoothened, andthe recess 212 may be better filled. FIG. 12A shows a perspective viewof a structure obtained after annealing processing is performed on thestructure in FIG. 11A. FIG. 12B and FIG. 12C are cross-sectionaldiagrams of FIG. 12A intercepted along a line A-A′ and a line B-B′,respectively. As shown in figures, the profile of the electrode materiallayer 402 is smooth.

Subsequently, as shown in FIG. 1, in step 113, a gate definingprocessing is performed. The gate defining processing may includeetching at least a portion of the stack layer to at least the seconddielectric layer so as to form a gate structure surrounding anintermediate portion of the nanowire. The gate structure includes aportion of the electrode material layer and the second dielectric layer.

In an implementation, the step of performing the gate definingprocessing may include: forming a third dielectric layer 502 to cover atleast the substrate structure and the area of the active region, asshown in FIG. 13A and FIG. 13B. FIG. 13A and FIG. 13B show sectionaldiagrams that are intercepted along a transverse direction of thenanowire 210 (the nanowire 210 is above the recess) (for example, adirection of the line A-A′ shown in the foregoing figures) andintercepted along a longitudinal direction of the nanowire 210 (forexample, a direction of the line B-B′ shown in the foregoing figures),respectively. The material of the third dielectric layer may include anoxide of silicon.

Subsequently, for example, as shown in FIG. 14A and FIG. 14B, the atleast a portion of the stack layer of the electrode material layer, thesecond dielectric layer, and the graphene layer is etched to at leastthe second dielectric layer 306 by using a patterned mask 504. As such,a gate structure surrounding an intermediate portion of the nanowire 210is formed. For example, the stack layer at a bottom portion of therecess 212 may be first etched by using dry etching, and then theelectrode material layer 402 under a portion of the nanowire 210 that isin the recess 212 and is not shielded is etched, so that the gatestructure is formed. The gate structure includes a portion of theelectrode material layer and the second dielectric layer. In a form,during this etching, the stack layer on a side wall of the recess 212 isetched and removed, as shown in FIG. 15A and FIG. 15B. In another form,the stack layer at the bottom portion and the side wall of the recess212 may also be removed in subsequent steps. In an implementation, theelectrode material layer 402 is used as a first gate, and the nanowire210 covered by the electrode material layer 402 is used as a secondgate.

Optionally, the method may further include a step of removing the stacklayer at the bottom portion and the side wall of the recess 212. Forexample, stack layer other than the bottom portion and the side wall ofthe recess 212 may be shielded by a patterned mask and the stack layerat the bottom portion and the side wall of the recess 212 may be removedusing a dry etching process. Cross-sectional diagrams of the obtainedstructure are shown in FIG. 16A and FIG. 16B, respectively.

Optionally, the method may further include a step of removing the thirddielectric layer 502. Moreover, a bottom portion of the electrodematerial layer is shaped, and a cross sectional profile of the shapedelectrode material layer 402 is circular, as shown in the perspectiveview of the obtained structure of FIG. 17.

Finally and optionally, as shown in FIG. 1, the method may furtherinclude step 115, which is a step of forming a contact component.

In an implementation, as shown in FIG. 18A, after the gate definingprocessing, a fourth dielectric layer 1701 may further be formed, so asto at least cover the substrate structure and the area of the activeregion. A material forming the fourth dielectric layer may include anoxide of silicon. Subsequently, a hole 1703 through the fourthdielectric layer and the second dielectric layer 306 to the graphenelayer 304 is formed. The hole 1703 (not shown in the figures, filledwith 1075) is separated from the gate structure. Then the hole is filledwith a conductive material, so as to form a contact component 1705 tothe graphene layer (i.e., may be an electrode contact component to asource/drain region).

FIG. 18A shows that the contact component 1705 is located at the supportportion 216 which is at the two ends of the nanowire 210 and is bondedthereto. However, it should be understood that, according to theteachings of the present disclosure, a person skilled in the art mayadjust the position of the contact component 1705 according to variousrequirements. For example, the contact component 1705 may be conceivedto be located at the nanowire (the nanowire crosses above the recess).

In an implementation, a doped nanowire 210 may be used as the secondgate (or, a back gate), as stated above. For example, as shown in FIG.18B, a fourth dielectric layer may be formed to at least cover thesubstrate structure and the area of the active region. A materialforming the fourth dielectric layer may include an oxide of silicon.Subsequently, a hole running through the fourth dielectric layer, thesecond dielectric layer 306, and the graphene layer 304 to the firstmaterial layer 204 (the nanowire 210) is formed. Next, an insulatingmaterial layer 1707 is formed on a side wall of the hole. Then, afterthe insulating material layer 1707 is formed, the hole is filled with aconductive material so as to form a contact component 1709 to at least aportion of the first material layer 204. Subsequently, the hole isfilled with a conductive material so as to form a contact component tothe first material layer (i.e., a second gate contact component), asshown in FIG. 18B.

In another implementation stated above, when the two ends of thenanowire 210 are separately bonded or connected to a portion of thefirst material 204 that are at the two ends of the recess 212 and abovethe first dielectric layer 202, the step of forming the contactcomponent (i.e., the second gate contact component) may include: forminga fourth dielectric layer, where the fourth dielectric layer at leastcovers the substrate structure and the area of the active region. Amaterial forming the fourth dielectric layer may include an oxide ofsilicon. Next, a hole passing through the fourth dielectric layer, thesecond dielectric layer 306, and the graphene layer 304 to at least aportion of the first material layer 204 is formed. Then, an insulatingmaterial layer is formed on a side wall of the hole. Subsequently, afterthe insulating material layer is formed, the hole is filled with aconductive material so as to form a contact component to the at least aportion of the first material layer, where the insulating material layerelectrically isolates the graphene layer from the contact component.

According to forms of the present disclosure, a new method formanufacturing a semiconductor device that introduces graphene isprovided. By using features and a dual-gate structure of graphene, theoperating current is better controlled and performances of a device areimproved.

It should be understood that this disclosure further teaches asemiconductor device, including: a substrate structure, the substratestructure including a substrate and a first material layer on thesubstrate, a recess being formed in the substrate, the first materiallayer including a nanowire, and the nanowire spanning the recess andbeing suspended above the recess; a base layer on an exposed surface ofthe nanowire; a graphene layer on the base layer; a second dielectriclayer on the graphene layer; and a gate structure surrounding anintermediate portion of the nanowire, where the gate structure includesa portion of the electrode material layer and the second dielectriclayer.

In an implementation, the substrate includes a substrate layer and afirst dielectric layer on the substrate layer, the first material layerbeing on the first dielectric layer, and the recess being formed in thefirst dielectric layer.

In an implementation, the recess further extends through the firstdielectric layer into the substrate layer.

In an implementation, the gate structure further includes a portion inthe recess below the nanowire.

In an implementation, the first material layer further includes aportion above the first dielectric layer at two ends of the recess, thetwo ends of the recess being bonded to the portion of the first materiallayer.

In an implementation, the first material layer is formed by polysilicon,or doped polysilicon or silicon germanium; the material of the baselayer includes an oxide of aluminum; the material of the firstdielectric layer includes an oxide of silicon; and the material of thesecond dielectric layer includes boron nitride, an oxide of silicon, anoxide of hafnium, an oxide of aluminum, or a nitride of aluminum.

In an implementation, the graphene layer is selectively grown on thebase layer.

In an implementation, the nanowire is formed by doped polysilicon; andthe portion of the electrode material layer that is included in the gatestructure is used as a first gate, and the nanowire is used as a secondgate.

In an implementation, the device further includes: a second base layeron an exposed surface of the recess; a second graphene layer on the baselayer; and a second dielectric layer on the second graphene layer, wherethe base layer is integrally formed with the second base layer, thegraphene layer is integrally formed with the second graphene layer, andthe second dielectric layer is integrally formed with the seconddielectric layer.

In an implementation, the device further includes: a fourth dielectriclayer, at least covering the substrate structure and the nanowire onwhich a stack layer of the base layer, the graphene layer, and thesecond dielectric layer is formed; a hole running through the fourthdielectric layer and the second dielectric layer to the graphene layer;and a contact component filling the hole and to the graphene layer.

In an implementation, the device further includes: a fourth dielectriclayer, at least covering the substrate structure and the nanowire onwhich a stack layer of the base layer, the graphene layer, and thesecond dielectric layer is formed; a hole running through the fourthdielectric layer, the second dielectric layer, and the graphene layer tothe first material layer; an insulating material layer on a side wall ofthe hole; and a contact component filling the hole and to the firstmaterial layer, where the insulating material layer electricallyisolates the graphene layer from the contact component.

In an implementation, the device further includes: a fourth dielectriclayer, at least covering the substrate structure and the nanowire onwhich a stack layer of the base layer, the graphene layer, and thesecond dielectric layer is formed; a hole running through the fourthdielectric layer, the second dielectric layer, and the graphene layer tothe portion of the first material layer; and a contact component whichis formed to the at least a portion of the first material layer byfilling the hole with a conductive material.

A semiconductor device and a manufacturing method therefor according tothe forms of this disclosure are described in detail above. To avoidobscuring the teaching of this disclosure, some details generally knownin this field are not described; and according to the description above,a person skilled in the art would completely understand how to implementa technical solution disclosed herein. In addition, this specificationdiscloses that the forms taught may be combined freely. A person skilledin the art should understand that various variations may be made to theforms described above without departing from the spirit and scope ofthis disclosure that are defined by the claims.

What is claimed is:
 1. A semiconductor device, comprising: a substratestructure comprising a substrate and a first material layer on thesubstrate, and a recess formed in the substrate, wherein the firstmaterial layer comprises a nanowire spanning and suspended above therecess; a base layer on an exposed surface of the nanowire; a graphenelayer on the base layer; a second dielectric layer on the graphenelayer; and a gate structure surrounding an intermediate portion of thenanowire, wherein the gate structure comprises a portion of the seconddielectric layer and an electrode material layer surrounding the portionof the second dielectric layer.
 2. The device according to claim 1,wherein: the substrate comprises a substrate layer and a firstdielectric layer on the substrate layer; the first material layer is onthe first dielectric layer; and the recess is formed in the firstdielectric layer.
 3. The device according to claim 2, wherein the recessfurther extends through the first dielectric layer into the substratelayer.
 4. The device according to claim 1, wherein the gate structurefurther comprises a portion in the recess below the nanowire.
 5. Thedevice according to claim 1, wherein the first material layer furthercomprises a portion above the first dielectric layer at two ends of therecess bonded to the portion of the first material layer forming thenanowire.
 6. The device according to claim 5, further comprising: afourth dielectric layer, covering at least the substrate structure andthe nanowire on which a stack layer of the base layer, the graphenelayer, and the second dielectric layer is formed; a hole through thefourth dielectric layer, the second dielectric layer, and the graphenelayer to the portion of the first material layer; and a contactcomponent to the at least a portion of the first material layer byfilling the hole with a conductive material.
 7. The device according toclaim 1, wherein: the first material layer comprises polysilicon, dopedpolysilicon, or silicon germanium; the base layer comprises an oxide ofaluminum; the first dielectric layer comprises an oxide of silicon; andthe second dielectric layer comprises boron nitride, an oxide ofsilicon, an oxide of hafnium, an oxide of aluminum, or a nitride ofaluminum.
 8. The device according to claim 1, wherein the graphene layeris selectively grown on the base layer.
 9. The device according to claim1, wherein: the nanowire comprises doped polysilicon; and the portion ofthe electrode material layer in the gate structure is used as a firstgate, and the nanowire is used as a second gate.
 10. The deviceaccording to claim 1, further comprising: a second base layer on anexposed surface of the recess; a second graphene layer on the secondbase layer; and a second dielectric layer on the second graphene layer,wherein the base layer is integrally formed with the second base layer,the graphene layer is integrally formed with the second graphene layer,and the second dielectric layer is integrally formed with the seconddielectric layer.
 11. The device according to claim 1, furthercomprising: a fourth dielectric layer, covering at least the substratestructure and the nanowire on which a stack layer of the base layer, thegraphene layer, and the second dielectric layer is formed; a holethrough the fourth dielectric layer and the second dielectric layer tothe graphene layer; and a contact component filling the hole and to thegraphene layer.
 12. The device according to claim 1, further comprising:a fourth dielectric layer, covering at least the substrate structure andthe nanowire on which a stack layer of the base layer, the graphenelayer, and the second dielectric layer is formed; a hole through thefourth dielectric layer, the second dielectric layer, and the graphenelayer to the first material layer; an insulating material layer on aside wall of the hole; and a contact component filling the hole and tothe first material layer, wherein the insulating material layerelectrically isolates the graphene layer from the contact component.